It's 1944 in France, over a month after the bloody D-Day landings. Allied armies are engaged in a life and death struggle against a determined German army. The outcome of the war hangs in the balance.
In the middle of the hellish fighting a bomb disposal unit of the Royal Canadian Army Engineers is assigned to disarm a tall boy, or earthquake bomb, the largest bomb in the British arsenal. The unexploded bomb is buried in the centre of a road critical to the allied armies advance and the German's are determined to stop them.
Lieutenant Gus Aimes must decide which of his remaining men will defuse this deadly bomb or die trying. The problem is no one has successfully disarmed a tall boy bomb before.